The present invention relates to devices for delivering, injecting, dispensing or administering substances, and to methods of making and using such devices. More particularly, it relates to an injection device comprising a needle cover for an injection needle which may be or is already affixed to the injection device at one end thereof, which may be referred to as the front end. The injection device may be used in self-administering an injectable product, for example insulin, a growth hormone or an osteoporosis medicine. In some embodiments, the injection device may be an injection pen.
The injection needle of an injection device poses a danger of injury, such as inadvertent sticks, contamination, etc., for example when exchanging the injection needle. Needles also may cause fear (needle phobia) in many patients who administer the product to themselves by injection, which can very well be the cause of an incorrect injection or at least a less than optimal injection. In order to reduce fear of the injection needle, injection devices are often provided with a needle blind or cover which surrounds and hides the needle in a protecting position, such that the user of the injection device in question cannot see the needle. The needle blind is usually held in the protecting position by a mechanical spring. For injecting, the user places the injection device onto the skin at the injection point and presses it against the skin, such that the needle blind is moved out of the protecting position, against the force of the spring, and the injection needle is simultaneously introduced into the body tissue. When the injection needle is removed from the body tissue, the needle blind automatically moves back into the protecting position due to the restoring force of the spring. In addition to the needle blind, a needle protector for injection devices is also known which is at least not primarily intended solely as a blind, but also to provide protection for the user against injuries from the injection needle. In the protecting position cited, the needle protector is locked and cannot be moved, for example, rearwardly, by a pressure force alone acting in the rearward direction, but only by destruction or by conscious, additional handling which releases a latch which is active in the protecting position. The needle protector can in principle expose the needle to view or, however, can also have the capacity of a blind, in addition to the function of protecting access.
U.S. Pat. No. 6,033,387 discloses an injection device embodied as a simple syringe with a protector protector. The needle protector encases the syringe completely and forms, so to speak, an outer casing for the syringe as a whole. When, after an injection, the needle protector has been moved into its protecting position by hand, it cannot be moved back out of the protecting position, or at least cannot be moved back into an assembling position until the syringe has been removed. In particular, there exists no injection position for the needle protector from which it automatically moves into the protecting position when the pressure is relieved.
In some embodiments, injection devices such as those to which the present invention relates may comprise a container holder into which a container filled with the product to be injected is inserted and, once consumed, replaced by a new container. In many cases, the container is an ampoule filled by the product manufacturer which is sealed at one end by an axially shifting piston and at another end by a sealing element. Since such injection devices are provided for an extended period of use with a number of consecutive product containers, the injection needles are also exchanged from time to time, for example together with the container. To this end, the injection needle is affixed to a needle holder connected to the injection device. When the needle holder is connected to the injection device, the injection needle pierces the sealing element of the container via a proximal (or rear or rearwardly facing) needle tip, such that a fluidic connection between the interior of the container and the injection needle is established.
Needle covers of this type, such as are known from, for example, DE 197 55 125 A1 and DE 100 09 816 A1, have a drawback in that they cannot be connected to the injection device until the needle holder has already been connected to the injection device. This has the result that the user has to affix the needle cover to the injection device while the injection needle is exposed and therefore has to work against the exposed injection needle, so to speak, when affixing the needle cover.